论文标题
太阳能电晕中的氦气线发射
Helium line emissivities in the solar corona
论文作者
论文摘要
我们在静态太阳电晕中提出了新的用于氦的碰撞辐射模型（CRMS），并预测了DKIST，太阳能轨道和Proba-3的He和He $^+$线的发射性。我们详细讨论了我们为这些模型选择的速度，重点介绍了我们在以前的工作中发现的几个缺陷。由于没有以前的完整且自一致的Coronal CRM，因此我们以10 $^{6} $ cm $^{ - 3} $的密度为最大的型号和20,000 K的温度和20,000 K的温度，而最近开发的用于光电离的Nebulae。然后，我们使用已经计算出的新的介电重组速率提出了外部太阳能电晕的结果，从而使中性氦气的丰度增加了约2倍。我们还发现，所有的光学三胞胎I线条，尤其是众所周知的I 10830和5876 A线受到磁盘辐射的光启示和光电等的强烈影响，并且需要广泛的CRM模型才能获得正确的估计。靠近阳光，以10 $^{8} $ cm $^{ - 3} $和1 mk的温度为10 $^{8} $^{8}的电子密度，我们预测He I 10830 a的发射率与强大的Fe XIII冠状线的发射率可比。我们确认，在304 a处的$^+$ lyman $α$也受到照相兴趣的显着影响，预计将被视为强大的冠状线，最高可达几个太阳能半径。
We present new collisional-radiative models (CRMs) for helium in the quiescent solar corona, and predict the emissivities of the He and He$^+$ lines to be observed by DKIST, Solar Orbiter, and Proba-3. We discuss in detail the rates we selected for these models, highlighting several shortcomings we have found in previous work. As no previous complete and self-consistent coronal CRM for helium existed, we have benchmarked our largest model at a density of 10$^{6}$ cm$^{-3}$ and temperature of 20,000 K against recent CRMs developed for photoionised nebulae. We then present results for the outer solar corona, using new dielectronic recombination rates we have calculated, which increase the abundance of neutral helium by about a factor of two. We also find that all the optical triplet He I lines, and in particular the well known He I 10830 and 5876 A lines are strongly affected by both photo-excitation and photo-ionisation from the disk radiation, and that extensive CRM models are required to obtain correct estimates. Close to the Sun, at an electron density of 10$^{8}$ cm$^{-3}$ and temperature of 1 MK, we predict the emissivity of the He I 10830 A to be comparable to that of the strong Fe XIII coronal line at 10798 A. However, we expect the He I emissivity to sharply fall in the outer corona, with respect to Fe XIII. We confirm that the He$^+$ Lyman $α$ at 304 A is also significantly affected by photo-excitation and is expected to be detectable as a strong coronal line up to several solar radii.
